460 



ANIMAL MECHANICS. 



Fig. io6.- — Dr. Haughtons Experiments — {Holding Arm hori 

 zontal) — Useful Effect, 



1 



wt = 



Aw 



A = 7730. "1 

 a = 8.5 lbs. j 



A valuable series of observations of the same kind have 

 been made by Mr. Jevons,* of which the following are the re- 

 sults : — 



Mr. Jevons Experiments — {Holding Arms horizontal). 



Weight. 



Time. 



Useful Effect. 



I lb. 



321 . 2 sees. 





2 „ 



218.9 „ 



438 



4 „ 



147.9 » 



592 



7 » 



87.4 » 



612 



10 „ 



60 3 v 



603 



14 „ 



3 2 -5 >j 



455 



I found equations (130) and (131) to represent the time 

 useful effect best, when 



A = 13340. 

 a = 10.9 lbs. 



By using these values 1 find the following comparison of 

 theory and observation. 



No. 1.— Mr. Jevons' Experiments — {Time of holding Arm 

 horizontal). 



w. 



t (observed). 



t (calculated) . 



Difference. 



I 



321 2 sees. 



3 20. 7 sees. 



+ 0.5 



2 



218.9 „ 



240- 3 » 



- 21.4 



4 



147 9 » 



'49-4 „ 



- '-5 



7 



87.4 „ 



86.1 „ 



+ i-3 



10 



60.3 ,, 



55-9 » 



+ 44 



14 



32-5 „ 



35-2 „ 



- 2.7 



* Nature, June 30, 1870, page 158. 



